Downloadable content (or DLC) are optional add-ons that grant additional gameplay options for a price. Mobile users purchase extras via in-app purchases offered within the app, an option not available to Mac and Windows users due to technical complications. Instead, add-ons may be offered via storefront.[1]

Gallery

Trivia

References

↑Disclaimer: We have yet to see how expansions will be distributed; Steam is known to support separate/purchasable DLC.
The team have confirmed that some expansions will be separate purchases, but not much is known at this point in time. Source: http://wolfquest.org/bb/viewtopic.php?p=2434053#p2434053